The thing that got Nixon was the cover-up,...
Add to that, John Dean's testimony, a democratic congress and two honest to god investigative reporters who had a boss that didn't care for RMN so much. Dean's testimony is what sank Nixon IMO. He could have weathered the others, maybe even the missing 18 minutes, until his 2nd term was over. But an insider who knew the real facts of the coverup and was willing to uphold what little honor he had left by coming forward... history in the making.
I don't know of too many elected and/or appointed officials or bureaucrats in DC that understand the concept of honor, let alone duty or country nowadays. Hopefully there is at least one, but no one seems to be forthcoming.
Sad that. We need a John Dean.